linux/include/net/nexthop.h
Eric Dumazet b1993a2de1 net: fix rtnh_ok()
syzbot reported :

BUG: KMSAN: uninit-value in rtnh_ok include/net/nexthop.h:11 [inline]
BUG: KMSAN: uninit-value in fib_count_nexthops net/ipv4/fib_semantics.c:469 [inline]
BUG: KMSAN: uninit-value in fib_create_info+0x554/0x8d20 net/ipv4/fib_semantics.c:1091

@remaining is an integer, coming from user space.
If it is negative we want rtnh_ok() to return false.

Fixes: 4e902c5741 ("[IPv4]: FIB configuration using struct fib_config")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-04-07 22:32:31 -04:00

35 lines
865 B
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __NET_NEXTHOP_H
#define __NET_NEXTHOP_H
#include <linux/rtnetlink.h>
#include <net/netlink.h>
static inline int rtnh_ok(const struct rtnexthop *rtnh, int remaining)
{
return remaining >= (int)sizeof(*rtnh) &&
rtnh->rtnh_len >= sizeof(*rtnh) &&
rtnh->rtnh_len <= remaining;
}
static inline struct rtnexthop *rtnh_next(const struct rtnexthop *rtnh,
int *remaining)
{
int totlen = NLA_ALIGN(rtnh->rtnh_len);
*remaining -= totlen;
return (struct rtnexthop *) ((char *) rtnh + totlen);
}
static inline struct nlattr *rtnh_attrs(const struct rtnexthop *rtnh)
{
return (struct nlattr *) ((char *) rtnh + NLA_ALIGN(sizeof(*rtnh)));
}
static inline int rtnh_attrlen(const struct rtnexthop *rtnh)
{
return rtnh->rtnh_len - NLA_ALIGN(sizeof(*rtnh));
}
#endif